1. Field of Invention
The present invention generally relates to a power surge detection device, and more particularly to a device for detecting power surges occurring in a computer system.
2. Description of Related Art
A power supply is an essential component in electrical equipment to provide the required power source. Computer systems are no exception. However, the reliability of a power source required by different electrical equipment can be quite different. A computer system typically requires a higher reliability from the power source so as to avoid data loss, calculation errors, or even system failures.
So far, emphasis on a power supply of a computer system is mainly on the following items:
1. The operating efficiency of the power supply: PA1 2. Overload voltage protection: PA1 3. Overload current protection:
A switching power supply is generally adopted in a computer system. Therefore, the load factor is maintained at a ratio of about 75%.about.85% to prevent overloading to the power supply itself. PA2 When the output voltage exceeds the rated voltage by 10%, the power supply is turned off to protect the circuit from being damaged. PA2 When the output current exceeds the rated current by 10%, the power supply is turned off to protect the circuit from being damaged and prevent further damages due to a short circuit from external circuits.
The power supply currently used in a computer system emphasizes on the above-mentioned protections. Generally, there is no power surge protection built within a computer system.
Power surges occur in many ways from, for example, lightning in the sky, or an operating machine that consumes large power. In the past, the computer can generally tolerate a poorer reliability from the power supply, because the operating speed and frequency are relatively low and the input/output voltages are relatively high. However, the operating speed of computers of the present generation has significantly increased. A central processing unit (CPU) has had an operating frequency up to several hundred MHz. With a pipe line computation, it can execute an instruction per one clock cycle. For example, the Pentium II CPU from INTEL, which adopts a specification of guning transceiver logic (GTL) PLUS bus, has a signal variation ranges from 0.about.1.5 volt. The threshold voltages for high and low levels are 1.0.+-.200 mV. As a result, the computer system allows only a relatively small range for voltage variation. A power surge to the computer system will significantly affect the input/output signals. Also, since the pipe line of the CPU is well designed, almost an instruction is executed for every clock cycle, which means data are continuously transmitted for every clock cycle. The power surge occurred not only damages the data transmitted from or to the CPU, but also causes data losses, calculation errors, or even system failures.
From the above-mentioned descriptions, it is understood that there is a deficiency in detecting a power surge in a conventional computer system to provide a stable power source required by the computer system that allows only a relatively small range for voltage variation. When a power surge occurs, data losses, calculation errors, or even system failures might occur to the computer system.